ACO: Distribute calculation over a cluster of machines

Currently implemented distributor is ERP5. See erp5_test_result from
https://github.com/erp5/erp5/tree/dream_distributor
The URL must be point to a DREAM Simulation Distributor, something like
http://localhost:55163/erp5/portal_task_distribution/dream_distributor

dream/simulation/GUI/ACO.py

@@ -3,6 +3,7 @@ import json
 import time
 import random
 import operator
+import xmlrpclib
 
 from dream.simulation.GUI.Default import Simulation as DefaultSimulation
 from dream.simulation.Queue import Queue
@@ -30,6 +31,14 @@ class Simulation(DefaultSimulation):
           "name": "Number of solutions",
           "_class": "Dream.Property",
           "_default": 4} )
+    conf["Dream-Configuration"]["property_list"].append(
+        { "id": "distributorURL",
+          "type": "string",
+          "name": "Distributor URL",
+          "description": "URL of an ERP5 Distributor, see "
+            "https://github.com/erp5/erp5/tree/dream_distributor",
+          "_class": "Dream.Property",
+          "_default": ''} )
     return conf
 
   def _preprocess(self, data):
@@ -59,8 +68,13 @@ class Simulation(DefaultSimulation):
   def run(self, data):
     data = self._preprocess(data)
 
+    distributor_url = data['general']['distributorURL']
+    distributor = None
+    if distributor_url:
+        distributor = xmlrpclib.Server(distributor_url)
+
     tested_ants = set()
-    start=time.time()         # start counting execution time
+    start = time.time()         # start counting execution time
 
     # the list of options collated into a dictionary for ease of referencing in
     # ManPy
@@ -74,9 +88,11 @@ class Simulation(DefaultSimulation):
 
     ants = [] #list of ants for keeping track of their performance
 
+
     # Number of times new ants are to be created, i.e. number of generations (a
     # generation can have more than 1 ant)
     for i in range(data["general"]["numberOfGenerations"]):
+        scenario_list = [] # for the distributor
         # number of ants created per generation
         for j in range(data["general"]["numberOfAntsPerGenerations"]):
             # an ant dictionary to contain rule to queue assignment information
@@ -91,22 +107,42 @@ class Simulation(DefaultSimulation):
             if ant_key not in tested_ants:
                 tested_ants.add(ant_key)
 
-                # the current ant to be simulated (evaluated) is added to the
-                # ants list
-                ants.append(ant)
-
                 # set scheduling rule on queues based on ant data
                 ant_data = copy(data)
                 for k, v in ant.items():
                     ant_data["nodes"][k]['schedulingRule'] = v
 
                 ant['key'] = ant_key
-
-                # TODO: those two steps have to be parallelized
-                ant['result'] = DefaultSimulation.runOneScenario(self, ant_data)
                 ant['input'] = ant_data
+
+                scenario_list.append(ant)
+
+        if distributor is None:
+            # synchronous
+            for ant in scenario_list:
+                ant['result'] = DefaultSimulation.runOneScenario(self, ant['input'])
+        else: # asynchronous
+            job_id = distributor.requestSimulationRun(
+                [json.dumps(x) for x in scenario_list])
+
+            print "Job registered", job_id
+            while True:
+                time.sleep(1.)
+                result_list = distributor.getJobResult(job_id)
+                # The distributor returns None when calculation is still ongoing,
+                # or the list of result in the same order.
+                if result_list is not None:
+                    print "Job terminated"
+                    break
+
+            for ant, result in zip(scenario_list, result_list):
+                ant['result'] = json.loads(result)
+
+        for ant in scenario_list:
             ant['score'] = self._calculateAntScore(ant)
 
+        ants.extend(scenario_list)
+
         # remove ants that outputs the same schedules
         ants_without_duplicates = dict()
         for ant in ants:
@@ -130,4 +166,5 @@ class Simulation(DefaultSimulation):
                 # selected by the next ants.
                 collated[m].append(l[m])
 
+    print "ACO finished, execution time %0.2fs" % (time.time() - start)
     return ants